<?php

if (!defined('BASEPATH'))
  exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2006 - 2012 EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 2.0
 * @filesource	
 */
// ------------------------------------------------------------------------

/**
 * CodeIgniter Memcached Caching Class 
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Core
 * @author		ExpressionEngine Dev Team
 * @link		
 */
class CI_Cache_file extends CI_Driver {

  protected $_cache_path;

  /**
   * Constructor
   */
  public function __construct() {
    $CI = & get_instance();
    $CI->load->helper('file');

    $path = $CI->config->item('cache_path');

    $this->_cache_path = ($path == '') ? APPPATH . 'cache/' : $path;
  }

  // ------------------------------------------------------------------------

  /**
   * Fetch from cache
   *
   * @param 	mixed		unique key id
   * @return 	mixed		data on success/false on failure
   */
  public function get($id) {
    if (!file_exists($this->_cache_path . $id)) {
      return FALSE;
    }

    $data = read_file($this->_cache_path . $id);
    $data = unserialize($data);

    if (time() > $data['time'] + $data['ttl']) {
      unlink($this->_cache_path . $id);
      return FALSE;
    }

    return $data['data'];
  }

  // ------------------------------------------------------------------------

  /**
   * Save into cache
   *
   * @param 	string		unique key
   * @param 	mixed		data to store
   * @param 	int			length of time (in seconds) the cache is valid 
   * 						- Default is 60 seconds
   * @return 	boolean		true on success/false on failure
   */
  public function save($id, $data, $ttl = 60) {
    $contents = array(
        'time' => time(),
        'ttl' => $ttl,
        'data' => $data
    );

    if (write_file($this->_cache_path . $id, serialize($contents))) {
      @chmod($this->_cache_path . $id, 0777);
      return TRUE;
    }

    return FALSE;
  }

  // ------------------------------------------------------------------------

  /**
   * Delete from Cache
   *
   * @param 	mixed		unique identifier of item in cache
   * @return 	boolean		true on success/false on failure
   */
  public function delete($id) {
    return unlink($this->_cache_path . $id);
  }

  // ------------------------------------------------------------------------

  /**
   * Clean the Cache
   *
   * @return 	boolean		false on failure/true on success
   */
  public function clean() {
    return delete_files($this->_cache_path);
  }

  // ------------------------------------------------------------------------

  /**
   * Cache Info
   *
   * Not supported by file-based caching
   *
   * @param 	string	user/filehits
   * @return 	mixed 	FALSE
   */
  public function cache_info($type = NULL) {
    return get_dir_file_info($this->_cache_path);
  }

  // ------------------------------------------------------------------------

  /**
   * Get Cache Metadata
   *
   * @param 	mixed		key to get cache metadata on
   * @return 	mixed		FALSE on failure, array on success.
   */
  public function get_metadata($id) {
    if (!file_exists($this->_cache_path . $id)) {
      return FALSE;
    }

    $data = read_file($this->_cache_path . $id);
    $data = unserialize($data);

    if (is_array($data)) {
      $mtime = filemtime($this->_cache_path . $id);

      if (!isset($data['ttl'])) {
        return FALSE;
      }

      return array(
          'expire' => $mtime + $data['ttl'],
          'mtime' => $mtime
      );
    }

    return FALSE;
  }

  // ------------------------------------------------------------------------

  /**
   * Is supported
   *
   * In the file driver, check to see that the cache directory is indeed writable
   * 
   * @return boolean
   */
  public function is_supported() {
    return is_really_writable($this->_cache_path);
  }

  // ------------------------------------------------------------------------
}

// End Class

/* End of file Cache_file.php */
/* Location: ./system/libraries/Cache/drivers/Cache_file.php */